Method and apparatus for determination of skin type

ABSTRACT

The skin type is determined by using at least one print carrier with an electrostatically chargeable printing surface, having a surface tension of less than 30 dynes per centimeter, for making an electrostatic sebum content imprint of the skin and for storing said electrostatic imprint on the stamp surface. Good determination of the facial skin type is achieved by taking an imprint each from the forehead, chin and both cheeks.

United States Patent Tur et al.

METHOD AND APPARATUS FOR DETERMINATION OF SKIN TYPE Inventors: Wladimir Tur, Mutschellen; Eugen Wyler, Kusnacht, both of Switzerland Assignee: Lovida AG, Oberwil, Switzerland Filed: Apr. 5, 1974 Appl. No: 458,394

Foreign Application Priority Data Apr. 16. 1973 Switzerland 5482/73 US. Cl. 128/2 W; 23/253 TP Int. Cl. A6113 10/00 Field of Search 128/2 W, 2 R; 23/253 TP;

273/96 E, lO6'B References Cited UNITED STATES PATENTS Krug et al, 128/2 W [451 Sept. 23, 1975 3,429,572 2/1969 Mars 273/95 E 3,544,1l3 12/1970 Hand 273/106 B 3,552,929 l/l97l Fields el al.. 128/2 W X 3,556.080 l/l97l Hein t 128/2 W 3.710.505 l/l973 Linenfelser t. 273/106 B X 3,784,200 l/l974 Hotchkiss 273/95 E Primary ExaminerKyle L. Howell Attorney, Agent, or Firm-Browdy and Neimark [57] ABSTRACT The skin type is determined by using at least one print carrier with an electrostatically chargeable printing surface, having a surface tension of less than 30 dynes per centimeter, for making an electrostatic sebum content imprint of the skin and for storing said electrostatic imprint on the stamp surface. Good determination of the facial skin type is achieved by taking an imprint each from the forehead, chin and both cheeks.

12 Claims, 6 Drawing Figures US Patent Sept. 23,1975

FIG. Z.

FIG. 2

FIG.3

FIG. 5A

METHOD AND APPARATUS FOR DETERMINATION OF SKIN TYPE FIELD OF INVENTION The invention concerns a method for determining skin type on the basis of the sebum content of the skin according to specific type groups. In addition, the invention concerns a device for the execution of this method.

BAC KGROU N D In dermatology and cosmetics, determination of skin types in accordance with the criteria of skin typing constitutes an important basis for effective and correct therapy and cosmetic care. Type classification is based on the fact that sebum production by the skin is essentially constant within a given skin type and reacts only very slowly to pharmacological stimuli and effects. In addition, the excretory ducts of the sebaceous glands are distributed more or less densely like a mosaic over the surface of the skin.

The study of the skin of the face or other skin areas is usually accomplished by visual examination and tactile determinations. The results of such a study depend in large measure on the area of the skin under study, the method employed and the ability of the person performing the study. Hence, personal experience is critical as far as reliable evaluation is concerned. Determination of skin type, ie normal, dry, oily and mixed, is carried out primarity subjectively and involves the danger of confusion and error, especially when transitional types of skin are involved.

The different types of skin differ from one another primarily in the amount of oil which is excreted, so that the quantitative determination of the amount of sebum on the surface of the skin, even if it is determined in relative values rather than absolute ones, allows determination of the skin type classification. This fact has lead to the development of a plurality of methods which are used to determine the amount of oil on the surface of the skin.

Thus, various diffusion methods have been described which are based on dissolving the skin oil with solvents. The solvents are then evaporated and the amount of oil remaining is weighed or determined by using analytical chemical methods. Furthermore, oil-absorption methods have been developed in which the skin oils are absorbed by cloth, filter paper, cellulose or cigarette paper. The oils are extracted from these materials and weighed, or a direct determination is made by staining the oil absorbed by the material directly with the appropriate dyes, e.g. osmic acid or Sudan black, and the amount determined colorimetrically.

With the aid of gas chromatography, as well as thinfilm chromatography, other, although very complicated, methods have been developed for determination of skin type.

Another method is the socalled sebograph. It is based on the displacement of an oil film floating on water by a small amount of skin oil. The skin oil is removed from the surface of the skin by means ofa metal rod and placed on the oil film. This causes a spreading spot from whose size the amount of free fatty acids in the skin oil can be determined.

Still another method is based on the change in transparency of ground glass by adhering oil. The spectrophotometric evaluation of such ground glass prints from the skin surface allow an indirect determination of the amount of oil.

All of these methods were developed for scientific purposes. They are generally very complicated and tedious, or else they produce research results which apply only to a very narrow area of the skin.

On the other hand, it is desirable for purposes of evaluating the condition of the skin, in addition to oil measurement, to have some idea of the skin topography. For this purpose, numerous methods have been developed and described. Thus, for example, plaster, adhesive strips, mirror glass and glass lens prints have been used. These methods give only very inaccurate or very short-lived prints, and simultaneous determination of the relative skin oil content is not possible.

SUMMARY An object of the invention is to overcome the defects of the prior art, such as indicated above; another object is to provide a method for determination of skin type and skin relief that can well be used in cosmetics; another object is to provide a method which is on the one hand offering relatively accessible results and on the other hand being capable of being carried out very simply, so that it can be used not only at cosmetic centers but also remotely, at least in part, by untrained persons. The evaluation of the test material, however, is carried out by trained personnel at especially established evaluation centers, due to their higher reliability.

The above objects are achieved by the invention by virtue of using at least one print carrier with an electrostatically chargeable printing surface with a surface tension of less than 30 dynes per centimeter. It is thereby possible to obtain an imprint of the skin, and subjecting the imprint on the print carrier in a subsequent optical auxiliary device to a separate evaluation step involving comparison decisions on the basis of established comparison criteria, and assignment to a specific group.

In this connection, it is possible, for example, to carry out a remote diagnosis, in which the necessary imprints are taken from the subject and the imprints themselves are analytically evaluated later on by skilled personnel. The print carriers can be sent to the subject by mail and after the imprints have been made can be returned in the same fashion to an evaluation point. The imprints remain unaffected for several days on the print carriers, so that a reliable evaluation is possible.

BRIEF DESCRIPTION OF DRAWING In the following, sample embodiments of the invention are described in greater detail with reference to the drawings.

The drawing shows the following:

FIG. 1 is a perspective view of a print carrier device described as an example of the invention, having four printing stamps in the carrier;

FIG. 2 is a perspective view of a printing stamp used with the device of FIG. 1;

FIG. 3 is a perspective view of a printing stamp according to a further sample embodiment;

FIG. 4 is a cross section through a recess in the device of FIG. 1, with printing stamp inserted; and

FIGS. 5A and 5B are plan views of imprints from oily skin and dry skin with flakes as seen through a stereo microscope.

DETAILED DESCRIPTION OF EMBODIMENTS According to FIG. 1, a print carrier box It) is pro vided with cylindrical recesses in which removeable printing stamps I], I2 and 13, I4 are located. The printing stamps according to FIG. 2 each consist, for example, of a cylindrical base I6 with a flat bottom and a handle 17 attached to the base. The diameter of the cylindrical base is 2.5 cm in the example so that the area of the base is approximately cm while the height of the handle is about 1 cm. The printing stamps are made of a plastic which can be easily charged electrostatically, and having a relatively low surface tension of about 30 dynes per cm, preferably approximately 20 dynes per cm. In addition to synthetic resins, other materials that will take an electrostatic charge can be used, such as natural resins. Experience has shown that the best results can be obtained if the material can be charged electrostatically to a value between 100 and 200 volts/cm. This value can be measured, for example, with the electrometer.

The materials that can preferably be used for the printing stamps include acrylic resin polymers, e.g., acrylic resin or polymethyl methacrylate. Preferably the printing stamps are black in color, in order that the imprint image to be described below can be viewed with maximum contrast.

In addition to the above-mentioned cylindrical shape, the printing stamps can have any other shape, e.g., a shape like that in FIG. 3, in which the base 18 is slightly curved.

According to FIG. 4, the printing stamp ll does not rest directly upon the bottom of the recess inside print carrier 10, but on an annular supporting shoulder 15. In this fashion the electrostatic imprint in the principal area of the printing stamp is preserved when the stamp is placed in the recess.

In order to be able to assign the printing stamps to various previously determined areas of the skin without confusion, such skin areas are numbered 1 to 4. Likewise, the recesses in the print carrier are numbered from I to 4.

The use of this device is as follows:

The stamp surface is dry cleaned before being used or mailed and by this operation the stamp surface becomes charged electrostatically. The charge remains on the surface for several days or even weeks.

Using the four black round printing stamps, imprints are taken individually from eg various areas of the skin of the face such as the forehead, chin and the two cheeks. In other words, the printing stamps contact the skin and by virtue of their electrostatic charge attract sebum and other accumulations from the skin to form an imprint. From these four imprints the skin type is determined by examination under a stereo microscope or a powerful magnifying glass.

In normal skin all four imprints show relatively uniform accumulations of oil droplets, no flakes and no large furrows or cracks. Under certain conditions the imprints of a few hairs may be visible.

In dry skin only scattered oil droplets or none at all will be found on all four imprints. On the other hand, flakes and small furrows and cracks may be visible.

In the oily type of skin, all four imprints will be covered densely with oil droplets. Coarse and uniform structures with cracks and furrows can be seen.

The mixed type on the basis of imprints from the forehead and chin shows a similar appearance to that for oily skin. in other words, thickly covcre with oil droplets. The imprints from the two chw' n the other hand, show the appearance of dry skin with scat tered or absent oil droplets and flakes.

In addition, the device described here makes it possible to difi'erentiate between oily-dry-flaky skin and dry' flaky skin. This is done as follows: if a few flakes are found on an imprint, an attempt is made to remove these flakes by blowing lightly on the imprint. If this is successful and the flakes fly off (which later can be read as a reduced number of flakes), dry-flaky skin is involved. If the number of flakes cannot be reduced by this measaure, the skin can be referred a as oily-dryflaky.

FIG. 5A shows an imprint of oily skin as seen through a stereo microscope. FIG. 53, on the other hand, shows the different appearance of dry skin with scattered dry flakes.

Another more careful examination of the imprints makes it possible not only to determine the relative oil content of the skin but also to get some idea of the skin surface topography. The skin relief (division into fields), lanugo hairs, skin modifications, skin defects and scars can all be seen quite well on the imprint.

What is claimed is:

l. A device for recording skin conditions for the determination of skin type on the basis of the sebum content of the skin, comprising a printing stamp having a smooth working surface for application against the skin, said working surface comprising means for electrostatically attracting and retaining sebum and other accumulations from the skin to thereby provide an electrostatic sebum content imprint of the skin,

said electrostatic attracting and retaining means consisting of an electrostatically charged material with a surface tension ofless than 30 dynes per centimeter.

2. Device according to claim I, wherein said printing stamp is made of natural or synthetic resin.

3. Device according to claim 2, wherein said printing stamp is made of an acrylic resin polymer.

4. Device according to claim I, wherein said printing stamp is made of a material which can be'electrostatically charged to a value between and 200 volts per 5. Device according to claim 2, wherein said printing stamp has a black color.

6. Device according to claim 1, wherein said printing stamp has a working surface area of at east 4 cm? 7. Device according to claim 1, wherein the working surface of said printing stamp is flat and circular.

8. Device according to claim I, wherein the working surface of said printing stamp is curved.

9. Device according to claim I, wherein four said printing stamps are contained in a print carrier consisting of high dielectric material to preserve any electrostatic charge on said stamp working surface, the print carrier being provided with corresponding recesses adapted to receive said printing stamps.

10. Device according to claim 9, wherein a supporting shoulder is provided around the side edge of the bottom of each said recess for supporting said printing stumps out of contact with the bottom surface of said recess.

11. Method for determining skin type on the basis of skin area on said imprinting surface, and the sebum content of the skin of certain type groups, examining said imprint on said imprinting surface by comprising comparison criteria to assign it to one of the speci charging an electrostatically chargeable imprinting fied type groups.

surface, having a surface tension of less than 30 5 12. Method according to claim 11, wherein one said dynes per centimeter, imprint is made each from the forehead, chin and both then contacting a skin area with said charged imcheeks for determination of the facial skin type.

printing surface to obtain a sebum imprint on said UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION PATENT N0. 3,906,933 DATED September 23, 1975 INVENTORtS) 3 Wladimir TUR et a1 it is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown beiowi Column 4, claim 2, line 42, after "wherein" insert -the working surface of-- Signed and Scaled this tenth Day of February 1976 [SEAL] RUTH C. MASON C. MARSHALL DANN Arresting Officer (mnmr'ssimu'r of Parents and Trademarks 

1. A device for recording skin conditions for the determination of skin type on the basis of the sebum content of the skin, comprising a printing stamp having a smooth working surface for application against the skin, said working surface comprising means for electrostatically attracting and retaining sebum and other accumulations from the skin to thereby provide an electrostatic sebum content imprint of the skin, said electrostatic attracting and retaining means consisting of an electrostatically charged material with a surface tension of less than 30 dynes per centimeter.
 2. Device according to claim 1, wherein said printing stamp is made of natural or synthetic resin.
 3. Device according to claim 2, wherein said printing stamp is made of an acrylic resin polymer.
 4. Device according to claim 1, wherein said printing stamp is made of a material which can be electrostatically charged to a value between 100 and 200 volts per cm.
 5. Device according to claim 2, wherein said printing stamp has a black color.
 6. Device according to claim 1, wherein said printing stamp has a working surface area of at least 4 cm2.
 7. Device according to claim 1, wherein the working surface of said printing stamp is flat and circular.
 8. Device according to claim 1, wherein the working surface of said printing stamp is curved.
 9. Device according to claim 1, wherein four said printing stamps are contained in a print carrier consisting of high dielectric material to preserve any electrostatic charge on said stamp working surface, the print carrier being provided with corresponding recesses adapted to receive said printing stamps.
 10. Device according to claim 9, wherein a supporting shoulder is provided around the side edge of the bottom of each said recess for supporting said printing stamps out of contact with the bottom surface of said recess.
 11. Method for determining skin type on the basis of the sebum content of the skin of certain type groups, comprising charging an electrostatically chargeable imprinting surface, having a surface tension of less than 30 dynes per centimeter, then contacting a skin area with said charged imprinting surface to obtain a sebum imprint on said skin area on said imprinting surface, and examining said imprint on said imprinting surface by comparison criteria to assign it to one of the specified type groups.
 12. Method according to claim 11, wherein one said imprint is made each from the forehead, chin and both cheeks for determination of the facial skin type. 